Friction drive mechanism



Dec. 16, 1958 s. A. BRETTELL, JR., ET AL 2,864,262

FRICTION omvs MECHANISM Original Filed Nov. 30. 1945 s Sheets-Sheet 1 N 64' SWITCHES l SET COURSE SPEED RUDDER CONTROL CONTROL INVENTOR.

GEORGE A. BRE T TELL, JR BY F/RTH PIERCE ATTORNEY Dec. 16, 1958 Original Filed Nov. 30, 1945 L 4 l n l l r l 50 I I k t 58 72 G. A. BRETTELL, JR., ET AL FRICTION DRIVE MECHANISM 3 Sheets-Sheet 2 INVENTOR GEORGE A. BRETTELL, JR. FIRTH PIERCE BY AZIOR/VEY DecQlG, 1958 a. A. BRETTELL, JR.. ETAL 2,354,262

FRICTION DRIVE MECHANISM Original Filed Nov. 30, 1945 3 Sheets-Sheet 3 Fig. .3

I INVENTOR. GEORGE A. BRETfELL, JR. FIRTH PIERCE ATTORNEY.

United States Patent FRICTION DRIVE MECHANISM George A. Bretell, Jr., and Firth Pierce, San Diego, Calif., assignors to the United States of America as represented by the Secretary of the Navy Original application November 30, 1945, Serial No. 631,946, now Patent No. 2,720,712, dated October 18, 1955. Divided and this application March 18, 1954, Serial No. 418,818

9 Claims. (Cl. 74-198) The present invention is related generally to teaching and practice equipment, and more particularly to a variable speed transmission.

This application is a divisional of application Serial No. 631,946, filed November 30, 1945, now Patent No. 2,720,712.

Fig. 1 is a simplified schematic diagram of the variable speed transmission.

Fig. 2 is a section through the mechanism of a ships conning controller and constitutes a section taken along the line 33 of Fig. 4 of parent case, Patent No. 2,720,712.

Fig. 3 is a sectional detail of Fig. 2.

Referring to Fig. l, a constant speed motor 50 drives a disk 52. A roller 54 in frictional engagement with disk 52 operates at a speed that depends on its distance from the center of the disk as controlled by speed adjusting knob 56. The speed of this roller 54 constitutes the ships speed. This speed is applied to a ball resolving mechanism 58 which generates the east and north components of the ships movement. It includes input roller 60 which drives a ball 62 which in turn drives output rollers 64 and 66. These rollers also drive a groupof switches, not shown in detail. The angular position of input roller 60 determines the relative speeds of the north and east output rollers 64 and 66 and therefore determines the ships course. This course is set by rudder simulating mechanism which operates as follows: Ships speed is applied to a disk 68 which drives two rollers 70 and 72 in opposite directions. A differential 74 takes the difference of the speeds of these two rollers to constitute the rate of ships turn, and the positions of the rollers 70 and 72 are set by a rudder control knob 75. Thus the rate of turning of the ship depends both on the rudder setting and also on the speed of the ship to simulate actual ship operation. For setting up problems a control 76 is provided for initially setting the ships course, To make this setting it is necessary to turn the knob 76 with sufiicient force to slide the rollers 70 and 72 on the face of the driving disk 68. 'The turning rate of the ship is applied to a gear 78 that controls the orientation of the input roller 60 of the ball resolver mechanism 58.

Figs. 2 and 3 show details of the speed and course mechanism in the ships conning unit. The constant speed motor 50, shown in Fig. 2, drives a gear 51 which in turns drives the disk 52. As may be seen best in Fig. 3, disk 52 drives a'roller 54 which has a ridge 53 which engages the driving surface of the disk 52 and has also a cylindrical surface which drives against a rim 55 on a second disk 59. The roller 54 is carriedon the shaft 150 which is equipped with circular grooves, or gear teeth, that are engage-d by a pinion 151 mounted on shaft 152. As shown in Fig. 2, this shaft 152 carries a gear 153 which is driven by speed setting knob 56. The speed indicator 57 consists of a dial mounted directly on gear 153.

' As shown in Fig. 3, the bushing 154 that supports shaft 150 also supports two ball bearing rollers 155 and 156 which respectively bear against the driving face of disk 52 2,864,262 Patented Dec. 16, 1958 and the rim 55 of the disk 59 to reduce the eccentric load imposed by the roller 54.

As is shown in Figs. 2 and 3, the roller 60 has a rim 61 which bears against disk 59 to be driven thereby, and the cylindrical portion of the roller 60 drives against the ball 62. The shaft 158 which supports the roller 60 is in turn supported in a ring 160 which turns in ball bearings 162. The ring 160 carries a gear 164 by which the roller 60 may be'oriented in accordance with the presumed heading of the ship. Roller 166 is also supported on shaft 158 and bears against the driving disk 59 to reduce eccentric loads. An idler roller 161 bears against the opposite side of the ball 62 to support the pressure exerted by roller 60. This roller 161 is similarly mount-' ed in a ring 163 which carries a gear 165.

As is shown in Fig. 2, disk 55 carries an annular gear 168 which drives an idler gear 170 which in turn drives disk 68 for the rudder control. The two rollers 70 and 72 which are driven by the disk 68, and the differential 74, constitute a unit held in frame 171 which ,is moved across the plate by a screw 172 which in turn is controlled by shaft 173 and'the rudder control handle 75.

As the frame 171 is moved, say, to the right from the zero position shown in Fig. 2, roller 72 moves away from the center of disk 68 and so runs faster, while roller 70 moves toward the center and reduces its speed. Since the differential 74 responds to the diiference in the speeds of the two rollers, the speed changes in the two rollers tend to drive the spider 174 in the same direction. The use of the two rollers 70 and 72 is especially advantageous here'because the rudder is likely to be left at center much of the time that the equipment is in operation. A

single outputroller would have to be set at the center of the disk for zero output and would rapidly wear a de-.

pression in the disk. With the present construction neither roller need ever be brought to the center of they disk. Zero output is obtained when the rollers 70 and 72 have the same speed. It will be readily appreciated that both the spacing between wheels 70, 72 as compared with the diameter of disk 68 and the length of the keyway which rotatably locks spider 174 to shaft 176 maintain the wheels on opposite sides of the disk axis at all times. Thus the change in the speed of rotation of shaft 176 is proportional to the sum of the decrease of one roller speed plus the concurrent increase of the other roller to keep idler 161 aligned with roller 60, gear 182 which drives selsyn generator 82, gear 184 which drives the compass card 80, and knob 76 for setting the course .at the beginning of the problem.

As may be seen from Figs. 2 and 3, thesphere 62,

which is driven about an axis parallel to shaft 158 by rotation of roller 60, may drive rollers 64, 66 at varying speeds relative to each other and to the speed of rotation of the sphere. These relative speeds are varied by angularly shifting or rotating the axis of rotation of the sphere relative to the axes of rollers 64, 66. Shifting of the sphere axis about the sphere center is effected through the mechanism including shaft which is responsive to rotation of the ball driving means including disk 59 and roller 60 and which operates to rotate shaft 158 about an axis perpendicular thereto and intersecting the sphere center. Rotation of shaft 158 about this perpendicular axis effectively shifts the axis of rotation of the sphere relative to the axes of rollers 64, 66 and thereby changes the roller speeds.

It will be apparent that the invention is not limited to the specific embodiment herein shown and described, but rather is capable of many variations within the scope of the claims.

We claim: i

1. In combination in a variable speed. drive, a disk, means for-driving the disk, a cylindrical roller having a ridge extendingabove. the cylindricalsurface, saidzridge lying in driven. engagement withsaid disk,',and output means engaging the cylindrical surface of said; roller and driven thereby, saidoutput means includes a disk-like member facing the firstdisk. so that the, roller lies between them, saidoutputdisk having a ridge-like portion engaging said cylindrical surface of ,the rolle r,and means for moving said roller across the face of the first disk, whereby assaid roller is.so moved, it maintains its driving engagement with both of said, disks.

2. In combination ina variablespeed drive, an input disk having a driving surface, arotatable output member substantially co-axial with said disk and facing the driving surface of the disk, said output member having a circular ridge,,a drive roller lying between said disk and said output member, said roller having a cylindrical surface engaging the ridge of the output member and having a ridge engaging the driving surface of the input disk, whereby the speed ratio between the input disk and the roller may be varied by moving the roller toward and away from the axis of rotation of the input disk but the speed ratio between the roller and the output disk is substantially constant.

3. The combination of the immediately preceding claim wherein the input disk and theoutput member are of approximately equal diameters and whereinthe driving ridge of the outputmember is at its perphery.

4. Thecombinationof claim 2 wherein there are included two idler rollers, one bearing against the driving face of the input disk and the other against the ridge of the. output member, said two rollers being mounted close to each other and supported together at a position approximately opposite the first roller, whereby to reduce eccentric loads on said driving disk and output member.

5. In combination in a computer, a rotatable input disk, a first roller having a narrow frictional rolling surface engaging the face of the input disk and having a cylindrical surface, a second disk lying substantially. co-axial with the input disk and having a ridge that presents a narrow frictional track to said cylindrical surface, whereby the speed ratio between said input disk and said first roller may be varied by moving the roller to move its pointof. contact with the input disk toward and away from the axis of rotation of said input disk but the speed ratio between said roller and the second disk. remains substantially constant, a second roller driven by said second disk and having a cylindrical surface near the axis of said disk, the axis of said second roller being substantially perpendicular to the axis of said second disk, a ball centered on the axis of said second disk and engaging said cylindrical surface, of said second roller to be driven thereby, output means driven by said ball, and

means for turning said second roller about the axis of said second disk whereby to rotate the axis about which said ball is rotated by said second roller.

6. In combination in a variable speed drive, a driving disk, a pair of relatively spaced friction wheels rotatably mounted on a common shaft lying parallel to the disk face, said wheels engaging said disk face on opposite sides of thedisk axis, said shaft being rotatably positioned within a movable frame member, means for moving said frame member and axially shifting said wheels and shaft, means for maintaining said wheels on said opposite sides of said disk axis to prevent rotation of said wheels in the same direction, means responsive to the difference between the speeds of rotation of said wheels for driving said common shaft.

7. In a device of the class described a rotatably mounted ball, means for driving a ball driving means, said ball driving means mounted for rotation about afirst axis for rotating said ball about a second axis parallel to said first axis, and second means for mounting said ball driving means for rotation about a third axis perpendicular to said first axis, whereby said first and second axes may be angularly shifted, control means responsive to movement of. said first mentioned means for moving said ball driving means about said third axis.

8. In a device of'the class described a rotatably mounted ball, means; for driving a ball driving means, said ball driving means mounted for rotation about a first axis for rotating said ball about a second axi parallel to said first axis, and second means for mounting said ball drivingmeans for rotation about a third axis perpendicular to said first axis, whereby said first and second axes. may be angularly shifted, control means responsive to movement of said. first mentioned means for moving said ball driving means about said third axis, said. control means including means for varying the speed of movement of said ball; driving means about said third axis relative to the speed of movement of said ball driving means about said first axis.

9. In a device of the class described. a sphere, means for rotating said sphere about a first axis intersecting the center thereof, driven means journalled on a second axis for rotation in response to rotation of said sphere, and means for angularly shifting one of said axes relative to the other about the center of said sphere to vary the speed ratio between said sphere and said driven means, wherein said axis shifting means includes means responsive to said sphere rotating means.

References Cited in the file of this patent UNITED STATES PATENTS 1,129,629 Berstter Feb. 23, 1915 1,348,822 Ricketts Aug. 3, 1920 2,218,651 Lenny Oct. 22, 1940 2,432,327 Moore Dec. 9, 1947 2,537,559 Tippen Jan. 9, 1951 2,586,421 Evers Feb, 19, 1952 

